Conversion of hydrocarbon oils



Aug. 10, 1937. .1. c. MORRELL CONYERSION 0F HYDROCARBON OILS File'dSept. 28, 1954 M. w w. 0 3 5 6 a 6 5/ mm 5 5 l. N v m m M N E 9 2 C. C M4 .w I 5 E E R C M m s F. 4 I O m M 5 O m 4 4 T l C i m 4 F 3 J J 9 m RG E mm c Iv LM m m UH TU. HC All S X u a 6 U 3 a m R U F INVENTOR JACQUEC. MORRELL TTO E Patented Aug. 10, 1937 iTED STATES PATENT CFFICECONVERSION OF HYDROCAR-BON OILS Application September 28, 1934, SerialNo. 745,875

16 Claims.

This invention particularly refers to an improved prccess for thefractional distillation of hydrocarbon oils of relatively Wide boilingrange, such as crude petroleum, for example, accompanied by thepyrolytic conversion, under independently controlled conditions, ofrelatively lowboiling and high-boiling fractions of the charging stockfrom the topping operation as well as selective further conversion,within the same system, of relatively low-boiling and high-boilingintermediate products of the process.

The present invention offers a unified system of simple form for thesimultaneous conversion of selected relatively low-boiling andhigh-boiling 1 fractions of the charging stock together, respectively,with selected relatively low-boiling and high-boiling fractions of theinsufficiently converted intermediate products of .the process, saidrelatively low-boiling and high-boiling fractions 20 each beingsubjected to the conditions of treatment particularly suited for theconversion of each to produce maximum yields of good quality motor fuel.

As a special feature of the present invention the g overhead vaporousproducts from the topping operation are preferably subjected, togetherwith low-boiling insufficiently converted intermediate products of thecracking operation, to conversion or reforming in a heating coil atrelatively high temperture conversion conditions and preferably theoverhead products from the topping operation are supplied to thisheating coil while still in vaporous state without being first subjectedto condensation, which would result in considerable loss of heat, inorder to obviate the use of a vapor pump to pass the hot vaporousproducts from the topping operation through said heating coil. thetopping operation is preferably conducted at a sumciently higherpressure than that employed in the heating coil to overcome the drop inpressure, due to friction, through the heating coil and succeedingportions of the equipment.

As another special feature of the present invention, conversion of thehighly heated relatively low-boiling materials from the high-temperatureheating coil is preferably arrested or retarded to a degree sufficientto prevent their excessive further conversion by cooling the same byindirect contact with charging stock for the process, which is therebyfurnished heat to effect or assist its fractional distillation, and/orby direct contact with the relatively cool higher boiling oils, such asselected relatively high-boiling products from the topping operationand/or selected relatively high-boiling insufficiently convertedintermediate products of the cracking operation, whereby heat isfurnished to said relatively high-boiling oils to efiect or assist theirconversion at a milder temperature than that to which the relativelylowboiling oils are subjected.

One specific embodiment of the present invention may comprise subjectinghydrocarbon oil charging stock for the process, comprising an oil ofrelatively wide boiling range, to fractional distillation at substantialsuperatmospheric pressure, whereby it is separated into relativelylowboiling fractions, comprising the overhead Vaporous products, andrelatively high-boiling fractions, comprising condensate or bottoms fromthe distilling operation, subjecting said low-boiling vaporous fractionsto conversion conditions of elevated temperature and superatmosphericpressure in the heating coil, introducing the stream of highly heatedproducts from said heating coil into an enlarged reaction chamber, alsomaintained at superatmosp-heric pressure, and commingling therewith saidhigh-boiling fractions of the charging stock, withdrawing both vaporousand liquid conversion products from the reaction chamber, subjecting thelatter to further vaporization at substantially reduced pressure,subjecting the vaporous conversion products, including those resultingfrom said further vaporization, to fractionation in a separatefractionating zone, whereby their insufficiently converted componentsare condensed as reflux condensate and separated into selectedrelatively low-boiling and high-boiling fractions, subjectingfractionated vapors of the desired end-boning point from said separatefractionating zone to condensation, collecting and separating theresulting distillate and gas, returning said relatively low-boilingfractions of the reflux condensate to the heating coil for furtherconversion, together with the lowboiling vaporous fractions of thecharging stock, and returning the relatively high-boiling fractions ofthe reflux condensate to the reaction chamber for further conversion.

As an alternative method of operation, which however, is not equivalentto the method above described, either the high-boiling fractions of thecharging stock or the high-boiling fractions of the reflux condensate orboth may, when de sired, be subjected in a separate heating coil tomilder conversion conditions than those to which the low-boilingfraction of the charging stock and low-boiling reflux condensate aresubjected, prior to the introduction of said high-boiling fractions intothe reaction chamber. In such cases the stream of heated products fromthe high temperature heating coil to which the relatively low-boilingoils are supplied will not be cooled upon commingling with the higherboiling oils to such an extent as when neither of said high-boiling oilsare subjected to conversion in a separate heating coil. It may,therefore, be desirable to partially cool the stream of highly heatedproducts from the high-temperature light oil heating coil, prior to itsintroduction into the reaction chamber in order to retard conversion ofthese products sufficiently to prevent excessive further conversion inthe reaction chamber. The present invention provides for cooling of thestream of heated products from the high-temperature light oil heatingcoil by indirectly contacting a regulated portion or all of said streamwith the hydrocarbon oil charging stock for the process which issubsequently supplied to the fractional distilling stage, therebyfurnishing a portion or all of the heat required for said fractionaldistillation of the charging stock.

It will be noted that the various features of the invention arecooperative and mutually contribute to produce the desired finalresults. The invention is, however, not limited to the use of all of thevarious features herein described in, a single operation and alternativemethods of oper ation are not to be considered equivalent. I

The accompanying diagrammatic drawing illustrates one specific form ofapparatus for carrying out the invention. A description of the operationof the process of the invention, as it may be accomplished in anapparatus such as illustrated, is included in the following descriptionof the drawing. Hydrocarbon oil charging stock for the process,preferably comprising an oil of relatively wide boiling range containingan appreciable quantity of both relatively low-boiling and relativelyhigh-boiling components, such as crude petroleum, for example, issupplied through line i and valve 2 to pump 3 wherefrom it may be fedthrough line 4, valve 5, heat exchanger 6, line 1 and valve 8 intodistilling column 9, entering this zone in substantially vaporized stateand being subjected therein to fractional distillation. In theparticular case here illustrated the heat required for fractionaldistillation of the charging stock may be supplied thereto in heatexchanger 6 by indirect contact and heat exchange between the chargingstock and highly heated conversion products of the process, which aresupplied to this zone as will be later more fully described. It is,however, also within the scope of the present invention to employ aheating coil of any conventional form for the charging stock or toimpart thereto all or a portion of the heat required for its fractionaldistillation in any other Well known manner, not illustrated.

Distilling column 9 is preferably operated at a substantialsuperatmospheric pressure in order to eliminate pumping of the overheadvaporous products from this zone supplied to the cracking coil. In thecase here illustrated, the charging stock is separated by fractionaldistillation in column 9 into a selected overhead vaporous product ofthe desired end-boiling point and bottoms,

which latter comprise components of the charging stock remainingunvaporized in column 9 as well as the components which are condensed inthis zone as reflux condensate. It is, of course, also within the scopeof the invention, particularly in case the charging stock contains anydesirable low-boiling, intermediate or high-boiling fractions which itis not desired to subject to conversion, to separate the charging stockinto more than two selected fractions and to withdraw said desirablecomponents such as, for example, straight-run gasoline of good antiknockvalue, lubricating oil, asphaltic material, etc., from the system byWell known means, not illustrated in the drawing.

The selected low-boiling components of the charging stock remainingunvaporized in column 9 are withdrawn, in the case here illustrated,from the upper portion of this zone through line Ml to be suppliedtherefrom through valve M to conversion or reforming in heating coil I2.

When desired, a regulated portion of the overhead vaporous product fromcolumn 9 may be subjected to condensation, by well known means notillustrated, for the purpose of forming distillate which may be utilizedas a refluxing medium in column 9 by recirculating said distillate tothe upper portion of this zone, by well known means not illustrated.This is only one of the many well known satisfactory methods which maybe employed for assisting fractionation in column 9 and maintaining thedesired vapor outlet temperature from this zone so as to control theend-boiling point of the materials subjected to conversion in heatingcoil l2.

Heating coil I2 is located within a furnace I3 of any suitable form bymeans of which the heat required for accomplishing the desiredconversion of the low-boiling components of the charging stock issupplied thereto. Heatingcoil I2 is also preferably operated at asubstantial superatmospheric pressure and the highly heated products aredischarged from this zone through line M and may be directed, all or inpart,

through valve E5 in this line and through heat exchanger 6, line It andvalve ll into reaction chamber 29. The highly heated products fromheating coil i2 passed, as illustrated, through heat exchanger 6 serveto supply to the charging stock all or a portion of the heat requiredfor its fractional distillation. When desired, all or a regulatedportion of the stream of hot vaporous products from heating coil l2 maybypass heat exchanger 6 by diverting the same from line Hi through line98 and valve 19 into line 56 and thence to reaction chamber 20.

In case all or a substantial portion of the highly heated products fromheating coil i2 are passed through heat exchanger 6 they will be cooledsufficiently by indirect contact with the charging stock in this zone tomaterially retard or arrest their further conversion, in which case aregulated portion or all of one or both of the other oils supplied toreaction chamber 29, which other oils comprising high-boiling fractionsof the. charging stock and high-boiling fractions of the insufficientlyconverted intermediate products of the process (reflux condensate, arepreferably subjected to conversion in heating coil 33, prior to theirintroduction into the reaction chamber.

In case only a minor portion or none of the highly heated products fromheating coil l2 are passed through heat exchanger 6 to be cooled byindirect contact with the charging stock the heat contained in theseproducts may be utilized to elfect or assist conversion of a portion orall of either or both of the relatively high-boiling oils supplied toreaction chamber 20 as will be later more fully described, in which casesaid high-boiling oils serve to cool the highly heated products fromheating coil l2 sufiiciently to prevent their excessive furtherconversion in reaction chamber 20,

In the case here illustrated the high-boiling fractions of the chargingstock withdrawn from the lower portion of column 9 through line 2| andvalve 22 to pump 23 are fed therefrom through line 26' and may beintroduced, all or in part, into reaction chamber through line 25 andvalve 26 or a regulated portion or all of this material may pass throughvalve 27 in line 24 into line 3! and thence to heating coil 33.

High-boiling fractions of the reflux condensate produced in fractionator46, as will be later more fully described, which reflux condensatecomprises the insufficiently converted intermediate products of theprocess are withdrawn from the lower portion of the fractionator throughline 28 and valve 29 to pump 30 by means of which they are fed throughline 3! and may pass, all or in part, through valve 32 in this line toconversion in heating coil 33 or a regulated portion or all of thismaterial may be supplied from line 3! through line 34 and valve 35 toreaction chamber 26.

Heating coil 33, when employed, is preferably operated at a substantialsuperatmospheric pressure and the oil supplied to this Zone is heated bymeans of heat supplied from a furnace 36 of any suitable form to thedesired conversion temperature which is preferably less than thatemployed at the outlet from heating coil !2. The heated products aredischarged from heating coil 33 through line 3? and valve 38 and, in thecase here illustrated, are directed through line i8 into reactionchamber 2!].

Reaction chamber 25 is preferably also operated at a substantialsuperatmospheric pressure. It will be understood, of course, that any orall of the various oils supplied to this zone may be separatelyintroduced thereto by well known means, not shown in the drawing,instead of being comrningled, as illustrated, prior to theirintroduction into the reaction chamber. In any case the relativelyhigh-boiling oils supplied to chamber 28 and particularly their vaporouscomponents are subjected to appreciable conversion in this zone byvirtue of the temperature and pressure conditions maintained therein,the heat required for such conversion being derived either from theheated products from heating coil [2 or supplied by means of heatingcoil 33 or from both sources. In the particular case here illustrated,both vaporous and liquid conversion products are withdrawn from thelower portion of chamber 20 through line 39 and valve 40 and areintroduced into vaporizing chamber 4!. It will be understood, however,that, when desired, all or a regulated portion of the vaporous productsmay be separately withdrawn from chamber 20 at any desired point in thiszone, by well known means not illustrated, in which case the separatelywithdrawn vapors may be supplied, all or in part, directly tofractionator 4G or may be introduced, all or in part, into vaporizingchamber 4! at any desired point in this zone, by well known means notShown in the drawing.

Chamber ll is preferably operated at a sub stantially reduced pressurerelative to that employed in the reaction chamber by means of whichfurther vaporization of the liquid conversion products supplied to thiszone from reaction chamber 20 is accomplished. Residual liquid remainingunvaporized in chamber 4! may be withdrawn from the lower portion oftlL's zone through line 42 and valve 43 to cooling and storage or to anydesired further treatment. The vapo rous products evolved in chamber Has well as any supplied to this zone from the reaction chamber may bedirected through line 44 and valve 45 to fractionation in fractionator4%, together with any vaporous products which may be supplied, aspreviously mentioned, to fractionator 46 direct from reaction chamber20.

The components of the vaporous products supplied to fractionator 36,including their fractions boiling above the range of the desired finallight distillate product of the process as well as, when desired,regulated quantities of selected high-boiling fractions within theboiling range of the desired light distillate product but of inferioranti-knock value, are condensed in this zone as reflux condensate and,in accordance with the features of the present invention, are separatedinto selected relatively low-boiling and high-boiling fractions. Thehigh-boiling fractions of the reflux condensate may be returned, asalready described, to heating coil 33 or to reaction chamber Zil or, inpart, to both for further conversion. The selected relatively lowboilingfractions of the refiuX condensate may be withdrawn from any suitableintermediate point or plurality of points in the fractionator and, inthe particular case here illustrated, are Withdrawn therefrom throughline 42 and valve 48 to pump 49 by means of which they are returnedthrough line 50 and valve 5! to further conversion in heating coil l2,together with the lowboiling fractions of the charging stock.

Fractionated vapors of the desired end-boiling point, preferablycomprising materials within the boiling range of motor fuel of goodantiknock value are withdrawn, together with uncondensable gas producedby the cracking operation from the upper portion 'of fractionator 46through line 52 and valve 53 to be subjected to condensation and coolingin condenser 54. The resulting distillate and gas passes through line 55and valve 56 to collection and separation in receiver 51. Uncondensablegas may be released from the receiver through line 58 and valve 59 toabsorption, storage or elsewhere, as desired. The distillate collectedin receiver 5'! may .1:

be withdrawn therefrom through line 60 and valve 6! to storage or to anydesired further treatment. When desired, a regulated portion of thedistillate collected in receiver 51 may be recirculated by well knownmeans, not illustrated in the drawing, to the upper portion offractionato-r 46 to serve as a refluxing and cooling medium in this zoneto assist fractionation of the vapors and to maintain the desired vaporoutlet temperature from the fractionator.

In a. process of the character illustrated and above described, thepreferred range of operating conditions may be approximately as follows:The temperature to which the charging stock is subjected for the purposeof effecting its fractional distillation may range, for example, from50G to- 800 F.-, or thereabouts, depending upon its characteristics, thedesired separation to be effected and upon the pressure employed in thefractional distilling stage of the process, which pressure may range,for example, from 100 to 500 pounds, or thereabouts, per square inch.The conversion temperature employed at the outlet from the heating coilto which the low-boiling fractions of the charging stock and theselected low-boiling fractions of the reflux condensate are supplied mayrange, for example, from 900 to 1100 F. and preferably a substantialsuperatmospheric pressure of the order of 200 to 500 pounds, or more,per square inch, is employed at this point of the system although, whendesired, lower pressures down to 100 pounds, or less, per square inch,may be employed in this zone. When a separate heating coil is employedfor conversion of high-boiling fractions of the charging stock orhigh-boiling fractions of the reflux condensate or both, the conversiontemperature employed at the outlet from this zone may range, forexample, from 800 to 950 F., or thereabouts, and preferably asuperatmospheric pressure of the order of 100 to 500 pounds, orthereabouts, per square inch, is employed at the outlet from thisheating coil. The reaction chamber is preferably operated at asubstantial superatmospheric pressure of the order of 100 to 500 pounds,per square inch, which pressure may be substantially the same orsomewhat less than the pressure employed in the light oil heating coilor in the heavy oil heating coil, in case the latter zone is employedand is operated at a lower pressure than that employed in the light oilcoil. The vaporizing chamber is preferably operated at a substantiallyreduced pressure relative to that employed in the reaction chamber whichmay range, for example, from substantially atmospheric pressure to 100pounds, thereabouts, per square inch superatmospheric. The pressureemployed the vaporizing chamber may be substantially equalized orsomewhat reduced in the succeeding fractionating, cOndensing andcollecting portions of the system.

As a specific example of one of the many possible operations of theprocess of the present invention, as it may be accomplished in anapparatus such as illustrated and above described, the

charging stock comprises a California crude of about 33 A.P.I. gravitycontaining approximately 34 percent of material boiling up to 437 F. andcontaining no appreciable amount of light ends boiling below 198 F. Thismaterial is heated to a temperature of approximately 700 F. by indirectcontact and heat exchange with the stream of highly heated products fromthe light oil heating coil of the system and is subjected to fractionaldistillation at a superatmospheric pressure of about 250 pounds persquare inch. The low-boiling fractions of the charging stock, comprisingits components boiling up to approximately 550 F. are subjected,together with lowboiling fractions of the reflux condensate, comprisingintermediate products of the cracking operation having a boiling rangeof approximately 350 to 600 F., are subjected in the light oil heatingcoil of the system to an outlet conversion temperature of approximately1000 F. with a superatmospheric pressure in this zone substantiallyequalized with that in the fractional distilling stage of the process.The high-boiling fractions, comprising about 42 percent, or thereabouts,of the charging stock, are subjected in a separate heating coil to anoutlet conversion temperature of approximately 950 F. at asuperatmospheric pressure of about 200 pounds per square inch and theheated products from this coil as well as the partially cooled productsfrom the light oil heating coil which, however, are still at atemperature appreciably within the conversion range are introduced intothe reaction chamber. High-boiling fractions of the reflux condensatefrom the fractionator of the cracking stage are also returned to thereaction chamber to commingle with the heated products from the twoheating coils and be subjected to further conversion therewith; Thereaction chamber is maintained at a superatmospheric pressuresubstantially equalized with that at the outlet from the light oilheating coil.

The vaporizing chamber is operated at a reduced pressure ofapproximately-50 pounds, per square inch, superatmospheric, and thispressure is substantially equalized in the succeeding fractionating,condensing and collecting portions of the system. This operation willproduce, per barrel of charging stock, approximately '72 percent of 400F. end-point motor fuel having an octane number of approximately 70 bythe motor method and approximately 15 percent of good quality residualliquid meeting specifications for premium fuel oil, the remainder beingchargeable, principally, to rich uncondensable gas.

I claim as my invention: 1

1. A process for the fractional distillation and selective conversion ofhydrocarbon oils which comprises subjecting hydrocarbon oil ofrelatively Wide boiling range to fractional distillation at substantialsuperatmospheric pressure whereby it is separated into selectedrelatively low-boiling and high-boiling fractions, withdrawing saidlowboiling fractions from the fractional distilling stage in vaporousstate and supplying the same without intentional condensation thereof toa heating coil, wherein they are subjected to conversion conditions ofelevated temperature and superatmospheric pressure, introducing theproducts from said heating coil into an enlarged reaction chamber alsomaintained at superatmospheric pressure and at a conversion temperature,introducing said selected high-boiling fractions of the charging stockinto said reaction chamber wherein they are subjected to conversion,withdrawing vaporous and liquid conversion products from the reactionchamber, subjecting the vaporous conversion products of the process tofractionation, whereby their insufiiciently converted components arecondensed as reflux condensate and separated into selected relativelylow-boiling and high-boiling fractions, subjecting fractionated vaporsof the desired end-boiling point to condensation, collecting theresulting distillate, returning said selected low-boiling fractions ofthe reflux condensate to the heating coil for further conversion,together with said low-boiling fractions of the charging stock, andreturning said high-boiling fractions of the reflux condensate to thereaction chamber for further conversion.

2. A process for the fractional distillation and selective conversion ofhydrocarbon oils which comprises subjecting hydrocarbon oil ofrelatively wide boiling range to fractional distillation at substantialsuperatmospheric pressure whereby it is separated into selectedrelatively low-boiling and high-boiling fractions, withdrawing saidlowboiling fractions from the fractional distilling stage in vaporousstate and supplying the same, without intentional condensation thereof,to a heating coil wherein they are subjected to conversion conditions ofelevated temperature and superatmospheric pressure, introducing theproducts from said heating coil into an enlarged reaction chamber alsomaintained at superatmospheric pressure and at a conversion temperature,introducing said selected high-boiling fractions of the charging stockinto said reaction chamber wherein they are subjected to conversion,withdrawing vaporous and liquid conversion products from the reactionchamber, subjecting the latter to further vaporization at substantiallyreduced pressure, subjecting the vaporous conversion products of theprocess to fractionation, whereby their insufficiently convertedcomponents are condensed as reflux condensate and separated intoselected relatively low-boiling and high-boiling fractions, subjectingfractionated vapors of the desired end-boiling point to condensation,collecting the resulting distillate, returning said selected low-boilingfractions of the reflux condensate to the heating coil for furtherconversion, together with said low-boiling fractions of the chargingstock, subjecting said high boiling fractions of the reflux condensateto independently controlled conversion conditions of elevatedtemperature and superatmospheric pressure in a separate heating coil andintroducing the resulting heated products into said reaction chamber.

3. A process for the fractional distillation and selective conversion ofhydrocarbon oils which comprises subjecting hydrocarbon oil ofrelatively wide boiling range to fractional distillation at substantialsuperatmospheric pressure, whereby it is separated into selectedrelatively lowboiling and high-boiling fractions, withdrawing saidlow-boiling fractions from the fractional distilling stage in vaporousstate and supplying the same without intentional condensation thereof toa heating coil wherein they are subjected to conversion conditions ofelevated temperature and superatmospheric pressure, introducing theproducts from said heating coil into an enlarged reaction chamber alsomaintained at superatmospheric pressure and at a conversion temperature,withdrawing vaporous and liquid conversion products from the reactionchamber, subjecting the latter to further vaporization at substantiallyreduced pressure, subjecting the vaporous conversion products of theprocess to fractionation, whereby their insufficiently convertedcomponents are condensed as reflux condensate and separated intoselected relatively low-boiling and high-boiling fractions, subjectingfractionated vapors of the desired end-boiling point to condensation,collecting the resulting distillate, returning said selected low-boilingfractions of the reflux condensate to the heating coil for furtherconversion, together with said low-boiling fractions of the chargingstock, and subjecting said selected high-boiling fractions of thecharging stock andv said high-boiling fractions of the reflux condensateto conversion within the same system under less severe conversionconditions than those to which said low-boiling fractions of thecharging stock and low-boiling fractions of the reflux condensate aresubjected.

i. A process as claimed in claim 3 wherein the stream of highly heatedproducts from said heating coil are cooled sufficiently to retard theirexcessive further conversion by indirect heat exchange with hydrocarbonoil charging stock for the process, whereby to furnish heat for saidfractional distillation of the charging stock.

5. A process as claimed in claim 3 wherein the stream of highly heatedproducts from said heating coil are cooled sufiiciently to retard theirexcessive further conversion by indirect heat exchange with hydrocarbonoil charging stock for the process, whereby to furnish heat for saidfractional distillation of the charging stock, and wherein said selectedhigh-boiling fractions of the charging stock are subjected toindependently controlled conversion conditions of elevated temperatureand superatmospheric pressure in a separate heating coil, the heatedproducts from said separate heating coil and said high-boiling fractionsof the reflux condensate being supplied to the reaction chamber.

6. A process as claimed in claim 3 wherein the stream of highly heatedproducts from said heating coil are cooled sufficiently to retard theirexcessive further conversion by indirect heat exchange with hydrocarbonoil charging stock for the process, whereby to furnish heat for saidfractional distillation of the charging stock, and wherein saidhigh-boiling fractions of the reflux condensate are subjected toindependently controlled conversion conditions of elevated temperatureand superatmospheric pressure in a separate heating coil, the heatedproducts from said separate heating coil and said selected highboilingfractions of the charging stock being supplied to the reaction chamber.

'7. A process as claimed in claim 3 wherein the stream of highly heatedproducts from said heating coil are cooled sufficiently to retard theirexcessive further conversion by indirect heat exchange with hydrocarbonoil charging stock for the process, whereby to furnish heat for saidfractional distillation of the charging stock, and wherein said selectedhigh-boiling fractions of the charging stock and said high-boilingfractions of the reflux condensate are subjected to independentlycontrolled conversion conditions of elevated temperature'andsuperatmospheric pressure in a separate heating coil, the heatedproducts from which are supplied to the reaction chamber.

8. A process as claimed in claim 3 wherein said selected high-boilingfractions of the charging stock are subjected to independentlycontrolled conversion conditions of elevated temperature andsuperatinospheric pressure in a separate heating coil, the heatedproducts from said separate heating coil and the high-boiling fractionsof the reflux condensate being supplied to said reaction chamber.

9. A process as claimed in claim 3 wherein the high-boiling fractions ofthe reflux condensate are subjected to independently controlledconversion conditions of elevated temperature and superatmosphericpressure in a separate heating coil, the heated products from saidseparate heating coil and said high-boiling fractions of the chargingstock being supplied to the reaction chamber.

10. A process as claimed in claim 3 wherein said selected high-boilingfractions of the charging stock and the high-boiling fractions of thereflux con-densate are subjected to independently controlled conversionconditions of elevated temperature and superatmospheric pressure in aseparate heating coil, the heated products from which are supplied tothe reaction chamber.

11. A process as claimed in claim 3 wherein said selected high-boilingfractions of the charging stock and the high-boiling fractions of thereflux condensate are commingled with the highly heated products fromsaid heating coil and subjected therewith to further conversion in thereaction chamber.

12. A process for producing anti-knock motor fuel from crude petroleumcontaining natural gasoline which comprises subjecting the crude tofractional distillation and separating selected relatively low-boilingand high-boiling fractions therefrom, supplying the selected low-boilingfractions, including the low anti-knock gasoline components of thecrude, to a heating coil, wherein they are subjected to conversionconditions of elevated temperature and superatmospheric pressureadequate to enhance the anti-knock value of said gasoline components,introducing the products from said heating coil into an enlargedreaction chamber also maintained at superatmospheric pressure and at aconversion temperature, introducing said selected high-boiling fractionsof the crude into said reaction chamber wherein they are subjected toconversion, withdrawing vaporous and liquid conversion products from thereaction chamber, subjecting the vaporous conversion products of theprocess to fractionation, whereby their insufliciently convertedcomponents are condensed as reflux condensate and separated intoselected relatively low-boiling and high-boiling fractions, subjectingfractionated vapors of the desired end-boiling point to condensation,collecting the resulting distillate, returning said selected low-boilingfractions of the reflux condensate to the heating coil for furtherconversion, together with said low-boiling fractions of the crude, andreturning said high-boiling fractions of the reflux condensate to thereaction chamber for further conversion.

13. The process as defined in claim 12 further characterized in thatsaid high-boiling fractions of the reflux condensate are subjected toindependently controlled conversion conditions of elevated temperatureand superatmosph-eric pressure in a separate heating coil prior to theirintroduction to the reaction chamber.

14. The process as defined in claim 12 further characterized in thatsaid high-boiling fractions of the crude are subjected to independentlycontrolled conversion conditions of elevated temperature andsuperatmospheric pressure in a separate heating coil prior to theirintroduction to the reaction chamber.

15. The process as defined in claim 1.2 further characterized in thatsaid high-boiling ;frac-: tions of the reflux condensate and of thecrude are subjected to independently controlled conversion conditions ofelevated temperature and superatmospheric pressure in a separate heatingcoil prior to their introduction to the reaction chamber.

16. A process for producing anti-knock motor fuel from crude petroleumcontaining natural gasoline which comprises subjecting the crude tofractional distillation and separating selected relatively low-boilingand high-boiling fractions therefrom, supplying the selected low-boilingfractions, including the low anti-knock gasoline components of thecrude, to a heating coil wherein they are subjected to conversionconditions of elevated temperature and superatmospheric pressureadequate to enhance the antie knock value of said gasoline components,introducing the products from said heating coil into an enlargedreaction chamber also maintained at superatmosp-heric pressure and at aconversion temperature, withdrawing vaporous and liquid conversionproducts from the reaction chamber, subjecting the latter to furthervaporization at substantially reduced pressure, subjecting the vaporousconversion products of the process to fractionation, whereby theirinsufliciently converted components are condensed as reflux condensateand separated into selected relatively low-boiling and high-boilingfractions, subjecting fractionated vapors of the desired end-boilingpoint to condensation, collecting the resulting distillate, returningsaid selected low-boiling fractions of the reflux condensate to theheating coil for further conversion, together with said low-boilingfractions of the crude, and subjecting said selected high-boilingfractions of the crude and said high-boiling fractions of the refluxcondensate to conversionwithin the same system under less severeconversion conditions than those to which said low-boiling fractions ofthe crude and low-boiling fractions of the reflux condensate aresubjected.

JACQUE C. MORRELL.

